On Tue, Feb 07, 2012 at 04:53:58AM -0800, Rok wrote: > > I am working on an application for astronomy and I would like to > measure so called dark current of a CCD (in electrons per second). > To do this I have to take pictures with shutter closed and at > different exposition times. > Is there a way to do this with android (or is there another way to get > dark current)?
*IF* (and I stress **IF**) I understand correctly, the shutter doesn't actually close, as such. The preview image you see is using the camera's sensor. When you take a picture, it just records the displayed image. My suggestion would be to use a very good shield to cover the lens (perhaps a deep black towel with the device resting on it ... in a tightly sealed box). It wouldn't be perfect, but it might be as good as you can get. Then, you could either use video mode rather than camera mode, and analyze each frame, or take repeated photos using the longest exposure time you can. Then do your analysis using (forgot the name) the process NASA, JPL, etc. use for deep space imagery, where they take multiple images of the same object and let the computer determine, by comparing ALL of them, what's real (i.e., stays in the image) and what's noise (moving or otherwise not constant). Hopefully someone here can tell you how to do it the right way...but if not, maybe this will help. Btw, to get a longer exposure, if your device supports it, use the SCENE_MODE_NIGHT parameter (see "Camera.Parameters" in the developers guide (http://developer.android.com) for more information. Later, --jim PS: I'm doing the studying right now, but am planning on working on a photo app, myself. There are a lot of features that I just can't find in any of the existing camera apps, most of which I'm fairly certain will prove to be easy...or at least, not insanely difficult. The others are probably impossible to do without an SLR or DSLR. -- THE SCORE: ME: 2 CANCER: 0 73 DE N5IAL (/4) MiSTie #49997 < Running FreeBSD 7.0 > [email protected] ICBM/Hurr.: 30.44406N 86.59909W "The iPad is a status symbol for yuppies. The Android is for people who actually want something that works." Android Apps Listing at http://www.jstrack.org/barcodes.html -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
